Gamexplain uploaded a video of the patch. They say it fixes a lot of the framerate issues.
https://www.youtube.com/watch?v=T1LNDsl3HJE
This is interesting and I do think there is something going on with his Xbox One. Those stutters that occur (independent of the alpha effects) simply DO NOT occur on any of our test systems here. I actually ran a good hour of gameplay in the first world through our frame-rate analysis tools and there was exactly one stutter and it was smaller than anything there.
Now, alpha effects in front of the camera do cause issues as it bumps up against the Xbox One's GPU capabilities (the game is 1080p like PS4). The reason it feels so dramatic is that it uses a double buffer v-sync just like Zelda Breath of the Wild so, like that game, the frame-rate drops to 20fps basically when it can't hold 30.
...but those kind of drops are very rare, actually. Those fire jets are pretty much the worst thing I've found in the first three worlds.
What's interesting is that, even pre-patch, I never ran into any of those massive stutters shown in the video...which highlights that issue I mentioned previously that Xbox One consoles seem highly variable depending on a number of unknown factors. I've seen exactly this kind of situation where on Xbox One system will have massive performance issues while another one is perfectly smooth. A reboot usually fixes this but not always. It's very odd. I believe what he is seeing in that video is not a fault of the game itself, rather, a fault of the Xbox One OS/hardware.
Which makes me think this might be a mileage may vary situation with most Xbox One consoles offering a stable experience while others might struggle. I spent more than six hours testing the game on Xbox One (more pre-patch) and was never able to trigger those massive stutters.
There also seems to be a weird expectation from everyone that this should have been 60fps but I just don't understand where that came from. This is a Unity game built by moderately small team and ported by a third party (Team 17) with huge maps. I mean, that it runs this stable is impressive especially when all versions are 1080p native. Coudl a game like this run at 60fps on consoles? With a custom engine, more money and a larger staff I'm sure it could be done but it was never going to happen in this situation. The biggest shame is the lack of PS4 Pro support, really.